Fluid pump and fluid machine

ABSTRACT

A fluid pump includes a driving part, a movable part that is movable by power transmitted from the driving part via a transmission part, a fixed part disposed on a side of the movable part, opposite to the transmission part, to form an operating chamber having an outlet from which a fluid flowing into the operating chamber is pressure-fed to an outside in a liquid state by the movable part, and an introduction passage for introducing a part of the fluid in the operating chamber to the transmission part. Accordingly, the liquid fluid can be introduced to the transmission part such as a bearing through the introduction passage.

CROSS REFERENCE TO RELATED APPLICATION

This application is based on Japanese Patent Applications No. 2005-58048 filed on Mar. 2, 2005, No. 2005-127909 filed on Apr. 26, 2005 and No. 2006-4017 filed on Jan. 11, 2006, the contents of which are incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a fluid pump applicable to a refrigerant pump for pressure-feeding, for example, a liquid refrigerant in a Rankine cycle to a heater. In addition, the present invention relates to a fluid machine used for the Rankine cycle. The fluid pump and the fluid machine can be suitably used for a vapor compression type refrigerator combined with a Rankine cycle.

2. Description of the Related Art

Conventionally, a fluid machine disclosed in, for example, JP-A-7-12068 is known as a fluid machine such as a compressor used for a refrigeration cycle. That is, this fluid machine is a scroll type machine and has a crankshaft for moving a revolving scroll. The shaft part of the crankshaft is rotatably supported by a bearing part and the crank part is connected to a revolving scroll via the bearing part in a back pressure chamber.

The crankshaft has an oil supply passage penetrating through in its axial direction, and this oil supply passage has an oil supply port and an oil supply groove that are open toward portions close to the bearing parts of the shaft part and the crank part. In a chamber of a casing of the fluid machine, the pressure of refrigerant is set at high pressure on a side opposite to the scroll of the crankshaft and is set at middle pressure in a back pressure chamber. Lubricating oil in the casing passes through the oil supply passage, the oil supply port and the oil supply groove, to respective bearings, by the pressure difference between the high pressure and the middle pressure to thereby lubricate the respective bearings.

However, in the above-described fluid machine, the oil supply passage, oil supply port, and the oil supply groove to the crankshaft need to be formed. In addition, in the casing, the high-pressure portion and the middle-pressure portion need to be set with respect to the crankshaft. This makes the structure of the fluid machine complex.

Moreover, the technology of using a compressor for a refrigeration cycle as an expander for a Rankine cycle in a vapor compression type refrigerator combined with a Rankine cycle is disclosed in JP-A-63-964494. Furthermore, US 2004/0,231,331 describes a fluid machine capable of recovering thermal energy with high efficiency in a vapor compression type refrigerator.

In US 2004/0,231,331, the direction of flow of refrigerant when a fluid machine is made to function as a compressor is reversed relative to that when the fluid machine is made to function as an expander by using a refrigerant pump of refrigerant pressure-feeding means for pressure-feeding refrigerant to the fluid machine, and thermal energy is converted to electric energy with high efficiency by providing a passage for transmitting power from the expander to a generator with a speed change mechanism.

The direction of flow of refrigerant in US 2004/0,231,331 will be described with reference to FIG. 22 and FIG. 23. When a fluid machine 202 integrated with an expander is operated as a compressor, power is supplied to the compression and expansion part 203 of the fluid machine 202 integrated with an expander, heat source is not supplied to a heater 213, and an open/close valve 218 is opened and a refrigerant pump 205 is not operated. Hence, as shown by arrows in FIG. 22, the refrigerant flows in the direction of: the fluid machine 202 integrated with an expander→the heater 213→the open/close valve 218→a radiator 207→a vapor-liquid separator 209→an expansion valve 211→an evaporator 212→the fluid machine 202 integrated with an expander. This is the same as the publicly known refrigeration cycle and heat absorbed by the refrigerant at the evaporator 212 is radiated at the radiator 207 to produce a refrigeration capacity.

Next, when the fluid machine 202 integrated with an expander is operated as an expander, a power storing battery 222 (storage battery) is connected to a driving and electric-power generating part 204 of the fluid machine 202 integrated with an expander, heat source is supplied to the heater 213, the open/close valve 218 is closed and the refrigerant pump 205 is operated. Hence, as shown by arrows in FIG. 23, the refrigerant flows in the direction of: the refrigerant pump 205→the heater 213→the fluid machine 202 integrated with an expander→a second bypass passage 220→the radiator 207→the vapor-liquid separator 209→a first bypass passage 220→the refrigerant pump 205. In this cycle, when the volume of the refrigerant heated by the heater 213 is expanded, the fluid machine 202 integrated with an expander generates mechanical energy and this mechanical energy is converted to electric energy to thereby recover thermal energy.

Generally, the refrigerant for the vapor compression type refrigerator (for example, HFC-134a) has lower viscosity than lubricating oil or water in the state of a liquid phase and the oil has the property of easily dissolving in liquid-phase refrigerant. For this reason, lubrication is apt to be insufficient in the mechanical sliding parts where only the liquid-phase refrigerant passes.

JP-A-63-96449 and US 2004/0,231,331 do not disclose anything about lubrication in the mechanical sliding parts of the refrigerant pump. However, in this refrigerant pump, the liquid-phase refrigerant separated by the vapor-liquid separator is sucked and discharged. That is, only the liquid-phase refrigerant passes over the mechanical sliding parts of the refrigerant pump and hence the mechanical sliding parts of the refrigerant pump are apt to be insufficiently lubricated.

Furthermore, JP-A-63-96449 and US 2004/0,231,331 disclose fluid machines applied to the vapor compression type refrigerator combined with a Rankine cycle, but also in a fluid machine designed specifically for a Rankine cycle, the mechanical sliding parts of the refrigerant pressure-feeding means are apt to be insufficiently lubricated because of the same reason.

SUMMARY OF THE INVENTION

In view of the foregoing problems, it is a first object of the present invention to provide a fluid pump which effectively introduce lubricating oil to a transmission part, e.g., bearings, with a simple structure.

It is a second object of the present invention to provide a fluid machine which effectively lubricates mechanical sliding parts in a refrigerant pressure-feeding member.

It is a third object of the present invention to provide a vapor compression type refrigerator combined with a Rankine cycle, which effectively lubricates mechanical sliding parts in a refrigerant pressure-feeding member.

According to an aspect of the present invention, a fluid pump includes a driving part, a movable part that is movable by power transmitted from the driving part, a transmission part through which the power from the driving part is transmitted to the movable part, a fixed part disposed on a side of the movable part opposite to the transmission part to form an operating chamber having an outlet from which a fluid flowing into the operating chamber is pressure-fed to an outside in a liquid state by the movable part, and an introduction passage for introducing a part of the fluid in the operating chamber to the transmission part. Therefore, liquid fluid can be easily supplied to the transmission part including bearings, and foreign subject in the bearings can be effectively discharged. Furthermore, when the transmission part including the bearings can be effectively lubricated using the liquid fluid including lubricating oil.

The introduction passage can be provided in the movable part, and the introduction passage has an opening part opened to the operating chamber to be tapered. Alternatively, the movable part includes a passage part for defining the introduction passage, and the passage part is a member separate from the movable part.

For example, the movable part is a movable scroll having a base plate portion and a first wall portion protruding from the base plate portion in a spiral shape, the fixed part is a fixed scroll having a spiral second wall portion engaged with the first wall portion. In this case, the introduction passage has a diameter smaller than a predetermined value, and is provided in the base plate portion of the movable scroll to make the operating chamber communicate with the transmission part at a predetermined pressure loss. Furthermore, the transmission part can be housed in a closed space. In this case, the movable scroll receives a back pressure applied thereto on a side of the fixed scroll by the fluid introduced into the closed space. In addition, the movable scroll can be provided with a plurality of holes, each having a diameter smaller than a predetermined value, for adjusting pressure between the operating chamber and the closed space.

Alternatively, the movable part can be a rotor that is made to revolve by the driving part arranged in a center of the movable part. In this case, the fixed part is a cylinder housing in which a cylinder housing the rotor is disposed, and the introduction passage is a passage having a diameter smaller than a predetermined value, and is provided in the rotor to make the operating chamber communicate with the transmission part at a predetermined pressure loss. The introduction passage may be a groove that is provided on an end surface in an axial direction of the rotor and makes the operating chamber communicate with the transmission part at a predetermined pressure loss.

According to another aspect of the present invention, a fluid machine includes: an expansion member having a function of outputting mechanical energy by expansion of refrigerant, the expansion member having a low-pressure port from which low-pressure vapor-phase refrigerant after being decompressed flows out and a high-pressure port from which high-pressure refrigerant before being decompressed flows in; an electric power generating member having a function of generating electric power by using the mechanical energy; a refrigerant pressure-feeding member for pressure-feeding refrigerant to the expansion member, the refrigerant pressure-feeding member having a refrigerant suction port from which liquid-phase refrigerant is sucked and a refrigerant discharge port from which liquid-phase refrigerant is discharged; and a communication part for making the low-pressure port of the expansion member communicate with the refrigerant suction port of the refrigerant pressure-feeding member. Furthermore, the communication part separates lubricating oil from vapor-phase refrigerant and supplies the lubricating oil to the refrigerant suction port. In this case, the fluid machine can effectively lubricate mechanical sliding parts in a refrigerant pressure-feeding member.

A housing can be provided to house all of the expansion member, the electric power generating member and the refrigerant pressure-feeding member. Furthermore, the low-pressure port can be arranged above the refrigerant suction port. For example, the expansion member having the low-pressure port is arranged above the electric power generating member, and the refrigerant pressure-feeding member having the refrigerant suction port is arranged below the electric power generating member. Furthermore, the communication part can separate the oil from the vapor-phase refrigerant by gravity by the use of a difference in specific gravity between the vapor-phase refrigerant and the oil and includes an oil storing part for storing the separated oil, and the oil storing part is provided in the electric power generating member.

The communication part can be provided with a check valve for preventing the liquid-phase refrigerant from flowing back from the refrigerant suction port to the low-pressure port. In this case, the communication part has a throttle mechanism connected in series to the check valve, and the throttle mechanism has a refrigerant passage area smaller than a refrigerant passage area of the check valve.

Furthermore, a transmission part for transmitting driving power from the expansion member to the refrigerant pressure-feeding member can be provided. In this case, the refrigerant pressure-feeding member is operated by the driving power from the expansion member. For example, the transmission part is a one-way clutch that transmits the mechanical energy as the driving power from the expansion member only when the expansion member outputs the mechanical energy.

The expansion member can be a compression and expansion member that has a function of compressing refrigerant by driving power applied thereto, and the electric power generating member can be a driving and electric-power generating member that applies the driving power to the compression and expansion member. In this case, when the compression and expansion member compresses refrigerant, the low-pressure port sucks low-pressure vapor-phase refrigerant after being decompressed and the high-pressure port discharges high-pressure refrigerant before being decompressed.

According to another aspect of the present invention, a fluid machine includes: an expansion member having a function of outputting mechanical energy by expansion of refrigerant; a refrigerant pressure-feeding member for pressure-feeding refrigerant to the expansion member, the expansion member having a low-pressure port from which low-pressure vapor-phase refrigerant after being decompressed flows out and a high-pressure port from which high-pressure refrigerant after being decompressed flows in, and a communication part that introduces oil contained in refrigerant flowing out from the low-pressure port to a sliding part of the refrigerant pressure-feeding member. Therefore, the fluid machine can effectively lubricate mechanical sliding parts in the refrigerant pressure-feeding member.

According to another aspect of the present invention, a vapor compression type refrigerator combined with a Rankine cycle includes: a compression and expansion member that has a function of compressing and discharging refrigerant by driving power applied thereto and a function of outputting mechanical energy by expansion of refrigerant, the compression and expansion member having a low-pressure port from which low-pressure refrigerant after being decompressed is sucked and flows out and a high-pressure port from which high-pressure refrigerant before being decompressed is discharged and flows in; a driving and electric-power generating member that has a function of applying the driving power to the compression and expansion member and a function of generating electric power by the mechanical energy; a refrigerant pressure-feeding member that pressure-feeds refrigerant to the compression and expansion member, the refrigerant pressure-feeding member having a refrigerant suction port from which liquid-phase refrigerant is sucked and a refrigerant discharge port from which liquid-phase refrigerant is discharged; and a communication part that makes the low-pressure port communicate with the refrigerant suction port. Furthermore, the communication part separates lubricating oil from the vapor-phase refrigerant and supplying the lubricating oil to the refrigerant suction port. Accordingly, mechanical sliding parts in the refrigerant pressure-feeding member can be effectively lubricated.

According to another aspect of the present invention, a vapor compression type refrigerator combined with a Rankine cycle, includes: a compression and expansion member that has a function of compressing and discharging refrigerant by driving power applied thereto and a function of outputting mechanical energy by expansion of refrigerant; a driving and electric-power generating member that has a function of applying the driving power to the compression and expansion member and a function of generating electric power by the mechanical energy; a refrigerant pressure-feeding member that pressure-feeds refrigerant to the compression and expansion member; a first communicating part through which a refrigerant suction side of the refrigerant pressure-feeding member communicates with a mechanical sliding portion of the refrigerant pressure-feeding member; and a second communication part that makes the low-pressure port communicate with the mechanical sliding portion. In addition, the second communication part separates lubricating oil from the vapor-phase refrigerant and supplying the lubricating oil to the mechanical sliding portion. Accordingly, the mechanical sliding portion of the refrigerant pressure-feeding member can be effectively and sufficiently lubricated.

BRIEF DESCRIPTION OF THE DRAWINGS

Additional objects and advantages of the present invention will be more readily apparent from the following detailed description of preferred embodiments when taken together with the accompanying drawings.

FIG. 1 is a cross-sectional view showing a refrigerant pump in a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a refrigerant pump in a second embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a small-diameter passage in a third embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a small-diameter passage in a fourth embodiment of the present invention.

FIG. 5 is a cross-sectional view showing a refrigerant pump in a fifth embodiment of the present invention.

FIG. 6 is a cross-sectional view showing a refrigerant pump in a sixth embodiment of the present invention.

FIG. 7 is a cross-sectional view taken on a line VII-VII in FIG. 6.

FIG. 8 is a cross-sectional view showing a refrigerant pump in a seventh embodiment of the present invention.

FIG. 9 is a cross-sectional view taken on a line IX-IX in FIG. 8.

FIG. 10 is a cross-sectional view taken on a line X-X in FIG. 9.

FIG. 11 is a schematic diagram showing an entire cycle construction of the eighth embodiment.

FIG. 12 is a cross-sectional view of a fluid machine integrated with an expander of the eighth embodiment.

FIG. 13 is a schematic sectional view showing a communication means of the eighth embodiment.

FIG. 14 is a cross-sectional view of a fluid machine integrated with an expander of a ninth embodiment.

FIG. 15 is a cross-sectional view of a fluid machine integrated with an expander of a tenth embodiment.

FIG. 16 is a schematic sectional view showing a communication means of the tenth embodiment.

FIG. 17 is a schematic diagram showing an entire cycle construction of an eleventh embodiment.

FIG. 18 is a schematic diagram showing an entire cycle construction of a twelfth embodiment.

FIG. 19 is a cross-sectional view of a fluid machine of a thirteenth embodiment.

FIG. 20 is a cross-sectional view taken on the line XX-XX in FIG. 19.

FIG. 21 is a cross-sectional view taken on the line XXI-XXI in FIG. 20.

FIG. 22 is a schematic diagram showing the direction of flow of refrigerant in a refrigerant cycle of a conventional example.

FIG. 23 is a schematic diagram showing the direction of another flow of refrigerant in a refrigerant cycle of the conventional example.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment

In this embodiment, a fluid pump in accordance with the present invention is typically used for a refrigerant pump 100 for pressure-feeding liquid refrigerant (corresponding to fluid in the present invention) in a Rankine cycle. Hereinafter, the basic construction of the refrigerant pump 100 will be descried by the use of FIG. 1. The Rankine cycle is a cycle that includes a refrigerant pump 100, a heater, an expander, and a condenser, which are connected to each other in the shape of a cycle. The Rankine cycle feeds liquid refrigerant from the refrigerant pump 100 to the heater and heats the liquid refrigerant by, for example, the waste heat of an internal combustion engine for a vehicle to produce superheated vapor and feeds the superheated vapor into the expander and recycles mechanical energy produced by the expansion of the refrigerant.

The refrigerant pump 100 in this embodiment is an electrically driven scroll type refrigerant pump that uses scrolls 112, 113 in a pump part 110 and has the pump part 110 driven by a motor part 120. The liquid refrigerant pressure-fed by the refrigerant pump 100 contains lubricating oil of order of several % for lubricating transmission parts such as bearing 114 d to be described later.

The pump part 110 is constructed of a fixed scroll (corresponding to a fixed part in the present invention) 112 fixed to a pump housing 111, a movable scroll (corresponding to a movable part in the present invention) 113 that revolves and shifts in position opposite to this fixed scroll 112, a pump shaft (corresponding to a driving part in the present invention) 114 for driving the movable scroll 113, and the like.

The fixed scroll 112 is constructed of a plate-shaped base plate portion 112 a and a spiral tooth portion (corresponding to a second wall part in the present invention) 112 b protruding from the base plate portions 112 a to the movable scroll 113. Meanwhile, the movable scroll 113 is constructed of a spiral tooth portion (corresponding to a first wall part in the present invention) 113 b, which is in contact with and is engaged with the tooth portion 112 b, and a base plate portion 113 a having this tooth portion 113 b formed thereon. The movable scroll 113 revolves in a state where both tooth portions 112 b, 113 b are in contact with each other to shift the position of an operating chamber V formed by both the scrolls 112, 113. The fixed scroll 112 has a discharge port 112 c, which communicates with the operating chamber V and is connected to the heater (not shown), formed in the center of the base plate portion 112 a.

The pump shaft 114 is a crankshaft having an eccentric portion 114 a formed eccentrically with respect to a rotational central axis at one end in a direction of length and is rotatably supported by the bearing 114 b fixed to the pump housing 111. A bushing 114 c is mounted on this eccentric portion 114 a in such a way to swing with respect to the eccentric portion 114 a (driven crank mechanism). This bushing 114 c is coupled to the movable scroll 113 via the bearing (corresponding to a transmission part in the present invention) 114 d. A side opposite to the eccentric portion of the pump shaft 114 is connected to the motor shaft 121 of the motor part 120. The bearing 114 d is a transmission part for transmitting a driving force to the pump mechanism and is a part including portion to be lubricated such as a sliding portion, a rolling portion or a friction portion.

A plate-shaped race 115 a and a plate-shaped retainer 115 b are fixed in layers to each of a surface on a side opposite to the fixed scroll of the movable scroll 113 and a surface of the pump housing 111, which is opposite to this surface, by bolts 115 d. Balls 115 e are interposed between tapered holes formed in each retainer 115 b. This construction forms a rotation preventing mechanism 115. The rotation preventing mechanism 115 prevents the movable scroll 113 from rotating while the pump shaft 114 rotates one rotation and causes the movable scroll 113 to revolve around the rotational center of the pump shaft 114.

In this embodiment, a small-diameter passage 113 c (corresponding to an introduction passage in the present invention) for making the operating chamber V communicate with the bearing 114 d at a specified pressure loss is formed in the central portion of the movable scroll 113. Here, as to the size of the small-diameter passage 113 c, its inside diameter “d” and length “L” (thickness of the movable scroll 113) are set at 0.1 mm and 6 mm, respectively, so as to prevent a large amount of liquid refrigerant from flowing from the operating chamber V to the bearing 114 d and to be able to be formed by actual machining (mechanical machining or electric discharge machining).

The amount of liquid refrigerant G pressure-fed by the refrigerant pump 100 is set at 230 kg/h and the validity of the flow rate AG (kg/h) of the liquid refrigerant flowing through the small-diameter passage 113 c is checked by the following mathematical equation 1 (Hagen-Poiseuille's Equation). ΔG=(π/8μ)×(ΔP/L)×(d/2)⁴×ρ×3600   (Mathematical equation 1) where μ is viscosity of liquid refrigerant (Pa), ΔP is a pressure difference (MPa) of liquid refrigerant applied to small-diameter passage 113 c, and ρ is density of liquid refrigerant (kg/m³)

Specifically, when it is assumed that d=0.1, L=6, μ=2×10⁻⁴, ΔP=2×10⁶, and ρ=1100, the flow rate ΔG of liquid refrigerant becomes 16 kg/h and is a level of 7% with respect to the amount of pressure-fed liquid refrigerant G (230 kg/h).

An open end on a side opposite to the operating chamber V of the small-diameter passage 113 c is open to the end surface of the eccentric portion 114 a. The cylindrical bushing 114 c is supported by the outside surface in the radial direction of the eccentric portion 114 a. The end surface of the eccentric portion 114 a and the end surface of the bushing 114 c are opposite to the base plate portion 113 a of the movable scroll 113 and a disk-shaped space is partitioned between them. The end portion of the movable scroll 113 side of the bearing 114 d is so positioned as to directly face the outside in the radial direction of this disk-shaped space. The movable scroll 113 has a cylindrical holding portion that is formed in a protruding manner and holds the bearing 114 d inside. The disk-shaped space communicates with a space partitioned outside in the radial direction of the holding portion through a space in the bearing 114 d or a space between the eccentric portion 114 a and the bushing 114 b. The rotation preventing mechanism 115 is arranged outside in the radial direction of this holding portion. In this construction, the small-diameter passage 113 c communicates with the disk-shaped space and this space reaches directly to the bearing 114 d. As a result, a passage is formed which passes through the small-diameter passage 113 c and reaches the bearing 114 d arranged on the back of the movable scroll 113.

Next, operation based on the above-described construction and operation effect will be described. When the pump shaft 114 is rotated by the operation of the motor part 120, the movable scroll 113 is made to revolve, the operating chamber V is displaced in such a way as to move from the outside diameter side of the movable scroll 113 to the center side. The liquid refrigerant, which is discharged from the condenser and flows into from a suction port (not shown), passes through the operating chamber V and is discharged from a discharge port 112 c and is pressure-fed to the heater.

In this embodiment, the movable scroll 113 has the small-diameter passage 113 c formed therein and hence a portion (corresponding to approximately 7% described above) of pressure-fed liquid refrigerant is positively introduced from the operating chamber V to the side of the bearing 114 d according to a pressure difference. Hence, by a simple structure that only the small-diameter passage 113 c is formed in the movable scroll 113, the bearing 114 d can be cooled and lubricated by lubricating oil contained in the liquid refrigerant to improve the reliability of the refrigerant pump 100. Conversely, when the reliability of the refrigerant pump 100 is maintained at the same level, the refrigerant pump 100 can be produced at lower cost. For example, it is possible to eliminate the need of selecting an expensive material for the bearing 114 d, or performing surface treatment or heat treatment to the bearing 114 d. Here, because fluid to be used is liquid (liquid refrigerant), unlike the case of gas, the small-diameter passage 113 c can be formed in a size (in particular, inside diameter d relating to the cross-sectional area of passage) that can be actually machined without being significantly affected by the amount of pressure-feed of liquid refrigerant and can produce the above-described effect.

Second Embodiment

The second embodiment in accordance with the present invention is shown in FIG. 2. The second embodiment is provided with a closed backpressure chamber 116 as compared with the above-described first embodiment.

Here, a sealing member 116 a is interposed between the movable scroll 113 and the pump housing 111 and another sealing member (not shown) is interposed between the pump shaft 114 (or a motor shaft 121) and the pump housing 111 to form the closed back-pressure chamber 116 on a side opposite to the fixed scroll of the movable scroll 113.

With this, the bearing 114 d can be lubricated by the liquid refrigerant introduced from the operating chamber V through the small-diameter passage 113 c and a back pressure (pressure applied to the fixed scroll 112) can be applied to the movable scroll 113. Hence, the thrust clearance between the movable scroll 113 and the fixed scroll 112 can be adjusted, which results in making it possible to eliminate the need for providing a specifically designed adjustment function. Since a pressure difference applied to the front and the back of the movable scroll 113 can be reduced, the set strength (for example, set thickness) of the movable scroll 113 can be decreased and hence the movable scroll 113 can be reduced in weight and cost. In the second embodiment, the other parts can be made similarly to the above-described first embodiment.

Third Embodiment

The third embodiment in accordance with the present invention is shown in FIG. 3. In the third embodiment, the shape of the small-diameter passage 113 c is changed as compared with the above-described first embodiment. That is, an opening of the small-diameter passage 113 c on the side of the operating chamber V has a tapered portion 113 d. The tapered portion 113 d provides the small-diameter passage 113 c with an opening. In the small-diameter passage 113 c, its most part is formed as a circular main portion having a specified small diameter and an opening is formed as the tapered portion in a tapered shape. In the tapered portion 113 d, the inside diameter of the small-diameter passage 113 c is gradually enlarged toward the operating chamber V. The tapered portion 113 d provides a circular opening having a diameter larger than the inside diameter of the small-diameter passage 113 c at the wall surface on the operating chamber V side of the base plate portion 11 3 a of the movable scroll 113. The tapered portion 113 d provides a wall surface shaped like a funnel that uniformly converges from the wall surface on the operating chamber V side of the base plate portion 113 a of the movable scroll 113 to the main portion of the small-diameter passage 113 c.

These shapes enable the liquid refrigerant to flow smoothly and to smooth the flow of the liquid refrigerant introduced into the bearing 114 d. In the third embodiment, the other parts can be made similarly to the above-described first embodiment or the second embodiment.

Fourth Embodiment

The fourth embodiment in accordance with the present invention is shown in FIG. 4. In the fourth embodiment, a portion where the small-diameter passage 113 c is formed is formed of a member separate from the movable scroll 113 as compared with the above-described first embodiment. That is, this separate member is previously formed as an orifice member 113 e having the small-diameter passage 113 c and this orifice member 113 e is fixed in the central portion of the base plate portion 11 3 a of the movable scroll 113 by press-in or the like.

Accordingly, it possible to form the small-diameter passage 113 c in the state of orifice member 113 e separated from the movable scroll 113 and hence to form the small-diameter passage 113 c with ease. In the fourth embodiment, the other parts can be made similarly to the above-described first embodiment.

Fifth Embodiment

The fifth embodiment in accordance with the present invention is shown in FIG. 5. In the fifth embodiment, an introduction passage is formed outside the refrigerant pump 100 as compared with the above-described first embodiment. That is, a return passage 131 communicating with the bearing 114 d is formed in a discharge side passage 130 connected from the discharge port 112 c to the heater and a throttle portion 132 corresponding to the small-diameter passage 113 c is formed in the middle of this return passage 131.

Accordingly, it possible to introduce a part of liquid refrigerant discharged from the discharge port 112 c into the bearing 114 d through the throttle portion 132 and to produce the same effect as the first embodiment.

Sixth Embodiment

The sixth embodiment in accordance with the present invention is shown in FIG. 6 and FIG. 7. In the sixth embodiment, the present invention is applied to a rotary vane type refrigerant pump 100A.

A pump part 110A of the rotary vane type refrigerant pump 100A includes a pump housing 111A, a cylinder housing 117, a pump housing 111B, a cylinder housing 117, a cylinder 117 a and a rotor 118 formed in an end housing 119, which are connected to each other in sequence. Here, the pump part 110A is a two-cylinder pump provided with two cylinders 117 a and two rotors 118. The end housing 119 has a suction port 119 a from which the liquid refrigerant is sucked, and a discharge port 119 b from which the liquid refrigerant flows out from the operating chamber V.

The cylinder 117 a is formed in a circular cross section in the central portion of the cylinder housing 117. The cylinder housing 117 corresponds to a fixed part in the present invention. The pump shaft 114A has a circular cam part 114 e, which is eccentric with respect to the pump shaft 114A, formed thereon, and a flat cylindrical rotor 118 is fitted on the outer peripheral side of this cam part 114 e via a bearing 114D (corresponding to a transmission part in the present invention). The rotor 118 corresponds to a movable part in the present invention. The rotor 118 has an outside diameter set smaller than the inside diameter of the cylinder 117 a and is inserted into the cylinder 117 a such that the rotor 118 revolves in the cylinder 117 a by the cam part 114 e. A vane 118 a, which can slide in the radial direction of the rotor 118 and is pressed toward the center to thereby abut against the rotor 118, is put in the outer peripheral portion of the rotor 118. A space surrounded by the rotor 118 and the vane 118 a is formed as the operating chamber V in the cylinder 117 a.

In the cylinder housing 117, a refrigerant inlet 117 b and a refrigerant outlet 117 c that communicate with the inside of the cylinder 117 a are formed close to the vane 118 a in such a way as to sandwich this vane 118 a. The refrigerant inlet 117 b is connected to the suction port 119 a by a passage (not shown) and the refrigerant outlet 117 c is connected to the discharge port 119 b by a passage (not shown).

In this embodiment, the small-diameter passages 113 c (e.g., two) each passing through the rotor 118 are formed at a first position between the refrigerant outlet 117 c of the rotor 118 and the vane 118 a and a second position opposite to the first position. For example, the two small-diameter passages 113 c are formed at positions opposite to each other across the center of the rotor 118, respectively. An outside opening end in the radial direction of the small-diameter passage 113 c is open to the outer peripheral surface of the rotor 118 and an inside opening end in the radial direction of the small-diameter passage 113 c is open to the inner peripheral surface of the rotor 118. The bearing 114D is located in a space between the rotor 118 and the cam part 114 e in the rotor 118. The small-diameter passage 113 c communicates with the space between the rotor 118 and the cam part 114 e.

In this refrigerant pump 100A, the liquid refrigerant flows from the suction port 119 a and the refrigerant inlet 117 b into the operating chamber V and flows out from the refrigerant outlet 117 c and the discharge port 119 b by the revolving operation of the rotor 118. A part of liquid refrigerant in the operating chamber V is introduced from the small-diameter passage 113 c into the bearing 114D. Hence, just as with the first embodiment, it is possible to have a lubricating effect on the bearing 114D and to improve the reliability of the refrigerant pump 100A.

In this embodiment, the liquid refrigerant is introduced so as to lubricate the bearing 114D. When the refrigerant is dispersedly mixed with lubricating oil, a higher lubricating operation can be expected. An open type bearing in which parts to be lubricated such as ball, roller, rolling surface, sliding surface are not enclosed can be used as the bearing 114D. For example, when an open type sliding bearing is used, the liquid refrigerant according to a pressure difference can be supplied to parts to be lubricated such as sliding part, rolling part, and friction part of the bearing 114D through the small-diameter passages 113 c formed in the rotor 118. In order to surely lubricate parts such as balls received between the inner ring and the outer ring of the bearing 114D, a through hole or a groove as a passage may be formed in bearing parts such as inner ring, outer ring, and cover. For example, a passage communicating with a hole made in the rotor 118 can be formed in the outer ring.

Seventh Embodiment

The seventh embodiment in accordance with the present invention is shown in FIG. 8 to FIG. 10. In the seventh embodiment, the small-diameter passages 113 c are changed to grooves 113 f as compared with the sixth embodiment.

The groove 113 f is a groove (see FIG. 10) that is formed in the end surface in the axial direction of the rotor 118 (for example, end surface on the right side of each rotor 118) and is circular in cross section. The groove 113 f is formed in such a way as to be straight in a longitudinal direction from the outer peripheral surface of the rotor 118 to the inner peripheral surface (see FIG. 9). Here, two grooves 113 f are formed at positions opposite to each other across the center of the rotor 118, respectively, in such a way as to oppose each other in the end surface in the axial direction of the rotor 118.

The above-described grooves 113 f forms introduction passages each having a lunate cross section between the rotor 118 and the pump housing 119 on the right side in FIG. 8 and between the rotor 118 and the pump housing 111B on the left side in FIG. 8 and causes the operating chamber V to communicate with the bearing 114D.

This introduction passage (groove 113 f) having a lunate cross section (arc section), just as with the above-described sixth embodiment, can introduce a part of liquid refrigerant from the operating chamber V to the bearing 114D and hence can produce an lubricating effect to the bearing 114D. Here, the introduction passage can be formed by forming the groove 113 f in the rotor 118 and hence can be easily formed as compared with the case of forming the small-diameter passage 113 c as described in the sixth embodiment.

As to the cross-sectional shape of the groove 113 f, the groove 113 f is preferably formed in the shape described in FIG. 9 and FIG. 10, but the groove 113 f is not necessarily formed in a circular shape but may be formed in a polygonal shape. Moreover, as to the longitudinal shape, the groove 113 f may be formed in a curved shape or in a circular shape. Furthermore, as to the number of grooves 113 f, one groove 113 f may be formed in the end surface in the axial direction of the rotor 118 and three or more grooves 13 f may be formed. In addition, the groove 113 f is formed not only in one surface of end surfaces in the axial direction of the rotor 118 (surface on the right side in FIG. 8) but also in both surfaces. As a result, the lubricating effect can be further enhanced.

Eight Embodiment

FIG. 11 is a diagram showing an entire cycle construction of a vapor compression type refrigerator for a vehicle in accordance with the eighth embodiment of the present invention. The vapor compression type refrigerator for a vehicle of this embodiment is a refrigerator combined with a Rankin cycle that produces cold and heat to air-condition a vehicle compartment and recovers thermal energy from waste heat produced in an engine 201.

First, a fluid machine 202 integrated with an expander is a fluid machine that is mounted in a vehicle engine room and is constructed of a compression and expansion part 203, a driving and electric-power generating part 204, a refrigerant pump 205, and an oil supply passage 206. The compression and expansion part 203, the driving and electric-power generating part 204, and the refrigerant pump 205 are combined into an integral structure and the fluid machine 202 integrated with an expander is formed in the shape of a cylinder in its entirety.

The compression and expansion part 203 is a compression and expansion means having: both of the function of a compressor for compressing and discharging refrigerant by a driving power applied thereto at the time of air-conditioning a vehicle compartment (hereinafter referred to as a compressor mode); and the function of outputting mechanical energy by the expansion of the refrigerant at the time of recovering thermal energy (hereinafter referred to as an expander mode). The compression and expansion part 203 has a low-pressure port 203 a from which low-pressure vapor-phase refrigerant is sucked and a high-pressure port 203 b from which high-pressure refrigerant is discharged and flows in.

The driving and electric-power generating part 204 is driving and electric-power generating means having both of the function of providing the compression and expansion part 203 with a driving force at the time of air-conditioning the vehicle compartment and the function of generating electric power by the mechanical energy outputted by the compression and expansion part 203 at the time of recovering thermal energy.

The refrigerant pump 205 is refrigerant pressure-feeding means for pressure-feeding liquid-phase refrigerant to the compression and expansion part 203 at the time of recovering thermal energy. The refrigerant pump 205 has a refrigerant suction port 205 a from which liquid-phase refrigerant is sucked and a refrigerant discharge port 205 b from which the liquid-phase refrigerant is discharged.

The oil supply passage 206 is communication means for causing the low-pressure port 203 a to communicate with the refrigerant suction port 205 a. The oil supply passage 206 is provided with an oil storing chamber 206 a for separating lubricating oil from the vapor-phase refrigerant and for storing the lubricating oil, and a check valve 206 c for allowing the oil flow from the low-pressure port 203 a only to the refrigerant suction port 205 a. The detailed descriptions of the other parts of the fluid machine 202 integrated with an expander will be provided.

Next, a radiator 207 radiates the heat of the refrigerant to cool the refrigerant, and the refrigerant inlet of the radiator 207 is connected to the high-pressure port 203 b of the fluid machine 202 integrated with an expander by a refrigerant piping 208.

A vapor-liquid separator 209 is a receiver that is connected to the refrigerant outlet of the radiator 207 and separates the refrigerant flowing out from the radiator 207 into vapor-phase refrigerant and liquid-phase refrigerant. Moreover, the vapor-liquid separator 209 is connected also to the refrigerant suction port 205 a by a first bypass passage 210.

The first bypass passage 210 is refrigerant piping for supplying the liquid-phase refrigerant separated by the vapor-liquid separator 209 to the refrigerant pump 205. The first bypass passage 210 is provided with a check valve 210 a for allowing the refrigerant to flow from the vapor-liquid separator 209 only to the refrigerant pump 205. Moreover, the refrigerant supplied to the refrigerant pump 205 is discharged from the refrigerant discharge port 205 b, and the refrigerant discharge port 205 b is connected to the refrigerant piping 208.

An expansion valve 211 is connected to the liquid-phase refrigerant outlet of the vapor-liquid separator 209 and reduces the pressure of the separated liquid-phase refrigerant to expand the refrigerant. This embodiment employs a temperature type expansion valve that reduces the pressure of the refrigerant isoenthalpically and controls a throttle opening in such a way that the degree of superheat of the refrigerant sucked into the low-pressure port 203 a of the fluid machine 202 integrated with an expander in the compressor mode approaches a specified value.

An evaporator 212 is a heat absorber that is connected to the expansion valve 211 and evaporates the refrigerant having its pressure reduced by the expansion valve 211 to effect a heat absorption action. The refrigerant outlet of the evaporator 212 is connected to the low-pressure port 203 a of the fluid machine 202 integrated with an expander. Refrigerant piping for connecting the evaporator 212 and the fluid machine 202 integrated with an expander is provided with a check valve 212 a, and the check valve 212 a allows the refrigerant to flow from the refrigerant outlet of the evaporator 212 only to the low-pressure port 203 a.

A heater 213 is a heat exchanger that is interposed between the high-pressure port 203 b of the refrigerant piping 208 and the connection portion of the refrigerant discharge port 205 b and exchanges heat between the refrigerant flowing through the refrigerant piping 208 and engine cooling water (hot water) to thereby heat the refrigerant.

Here, the engine cooling water is circulated through a hot water circuit 214 shown by a broken line in FIG. 11 so as to cool the engine 201. A water pump 215 of the hot water circuit 214 is an electrically driven pump for circulating the engine cooling water. A three-way valve 216 is an electromagnetic valve for switching between a circuit for introducing the engine cooling water flowing out from the engine 201 into the heater 213 and a circuit for not introducing the engine cooling water into the heater 213 but causing the engine cooling water to bypass the heater 213. Moreover, a radiator 217 is a heat exchanger that exchanges heat between the engine cooling water and the outside air to thereby cool the engine cooling water.

An open/close valve 218 is provided between the connection portion of the refrigerant discharge port 205 b to the refrigerant piping 208 and the radiator 207, and is an electromagnetic valve that opens/closes the refrigerant piping 208. A control valve 219 is interposed between the high-pressure port 203 b of the refrigerant piping 208 and the heater 213, and is an electromagnetic valve that functions as a discharge valve, that is, a check valve for allowing the refrigerant to flow from the high-pressure port 203 b only to the heater 213 in the compressor mode and is brought into a valve opening state in the expander mode.

A second bypass passage 220 is refrigerant piping for connecting the low-pressure port 203 a of the fluid machine 202 integrated with an expander and the refrigerant inlet of the radiator 207. The second bypass passage 220 is provided with a check valve 220 a for allowing the refrigerant to flow from the low-pressure port 203 a only to the radiator 207.

A control unit 221 performs, according to the operating mode of the fluid machine 202 integrated with an expander, the control of: supplying electric power to a driving and electric-power generating part 204; connecting the driving and electric-power generating part 204 to an electric power storage battery 222; switching the three-way valve 216; the open/close valve 218; and the control valve 219.

Next, the detail of the fluid machine 202 integrated with an expander will be described with reference to the cross-sectional view in FIG. 12. Arrows shown in the drawing indicate an up and down direction (vertical direction) when the fluid machine 202 integrated with an expander is mounted in a vehicle engine room.

First, the compression and expansion part 203 will be now described. The compression and expansion part 203 is arranged on the uppermost portion of the fluid machine 202 integrated with an expander and is provided with a mechanism for compressing and expanding the refrigerant. This compression and expansion mechanism can be made to a structure similarly to the publicly known scroll type compression mechanism.

Specifically, the compression and expansion part 203 includes: an upper housing 301; a middle housing 302; a shaft 303; a fixed scroll (shell) 304 of a fixed part that is formed integrally with the upper housing 301; a revolving scroll 305 of a movable part that revolves and shifts in position in a space between the middle housing 302 and the fixed scroll 304; an operating chamber 306 of a space which is formed between the fixed scroll 304 and the revolving scroll 305 and in which the refrigerant is compressed and expanded; a low-pressure port 203 a which communicates with the operating chamber 306 and from which the refrigerant is sucked and flows out; a high-pressure port 203 b which communicates with the operating chamber 306 and from which the refrigerant is discharged and flows in; and the like.

The upper housing 301 and the middle housing 302 act as protecting members for protecting the compression and expansion part 203. The upper housing 301 is integrally constructed of the fixed scroll 304, and have the high-pressure port 203 b and the low-pressure port 203 a. The upper housing 301 and the middle housing 302 are coupled to each other by screws via a sealing member such as gasket and O-ring (not shown) and are adapted to prevent the refrigerant from leaking from a joined portion.

The shaft 303 is a crankshaft supported by the middle housing 302 via a ball bearing 307 and provided with an eccentric part 308 that is eccentric with respect to the rotational central axis to an upper end side in the axial direction. The eccentric part 308 has the revolving scroll 305 rotatably coupled thereto via a needle bearing 309.

The fixed scroll 304 is constructed of a plate-shaped base plate portion 304 and a spiral tooth portion 304 b protruding from the base plate portion 304 a toward the middle housing 302 (in the down direction). Meanwhile, the revolving scroll 305 (movable scroll) is constructed of a spiral tooth portion 305 b, which is in contact with and is engaged with the tooth portion 304 b of the fixed scroll 304, and a base plate portion 305 a having the tooth portion 305 b formed thereon.

Further, a rotation preventing mechanism (not shown) is interposed between the revolving scroll 305 and the middle housing 302. The rotation preventing mechanism causes the revolving scroll 305 to revolve around the eccentric portion 308 one revolution while the shaft 303 rotates one rotation. When the shaft 303 rotates, the revolving scroll 305 does not rotate but revolves around the rotational central axis of the shaft 303. In this embodiment, a pin-ring (pin-hole) type mechanism is employed as the rotation preventing mechanism.

The low-pressure port 203 a is an inlet/outlet of the low-pressure refrigerant formed in the outer peripheral portion of the upper housing 301 and communicates with the outermost diameter portion of the operating chamber 306. The high-pressure port 203 b is an inlet/outlet of the high-pressure refrigerant formed in the upper portion of the upper housing 301 and is formed at a position communicating with the operating chamber 306 in the state of the smallest volume.

Next, the driving and electric-power generating part 204 will be described. The driving and electric-power generating part 204 is arranged below the compression and expansion part 203 in the middle housing 302 and is provided with a mechanism for driving the compression and expansion part 203 and for generating electric power. This driving and electric power generating mechanism has the same structure as a publicly known direct current motor.

Specifically, the driving and electric-power generating part 204 is constructed of the middle housing 302, the shaft 303, a stator 401, a rotor 402 rotating in the stator 401, a coupling part housing 403 for supporting the shaft 303, and the like.

The middle housing 302 and the coupling part housing 403 act as the protecting members of the driving and electric-power generating part 204. The middle housing 302 and the coupling part housing 403 are coupled to each other by screws via sealing members such as gasket and O-ring and are adapted to prevent the refrigerant from leaking from a coupled portion between the middle housing 302 and the coupling part housing 403. Moreover, the middle housing 302 and the shaft 303 are common to the constituent parts of the compression and expansion part 203 so as to reduce the size of the fluid machine.

The stator 401 is a stator coil having a winding wound thereon and is fixed to the inner wall surface of the middle housing 302. The rotor 402 is a magnet rotor having a permanent magnet berried therein and has a key groove 404 formed on the inner peripheral side and is fixed to the shaft 303 by a key.

The coupling part housing 403 has a protrusion 403 a protruding to the middle housing (in the upper direction) in the shape of a steeple head. An end portion opposite to (at the lower end in the axial direction of) the eccentric part 308 of the shaft 303 is supported by this protrusion 403 a via a ball bearing 405. A lip seal 406 for preventing the leakage of the refrigerant and oil between the driving and electric-power generating part 204 and the refrigerant pump 205 is interposed between the ball bearing 405 and the coupling part housing 403.

A space, formed by the inner wall surface of the middle housing 302 and the wall surface on the protrusion 403 a side of the coupling part housing 403, forms a space in which the shaft 303, the stator 401 and the rotor 402 are arranged and at the same time, forms an oil storing chamber 206 a in a remaining space where these parts are not arranged. The oil storing chamber 206 a is oil storing means for separating oil from the vapor-phase refrigerant and for storing the separated oil.

Furthermore, in the protrusion 403 a, there is provided with a communication hole 206 b for causing the oil storing chamber 206 a to communicate with the refrigerant suction port 205 a of the refrigerant pump 205. In the communication hole 206 b, a check valve 206 c is provided to allow the oil to flow from the oil storing chamber 206 a only to the refrigerant pump 205. Moreover, an orifice 206 d is formed on the downstream side of the check valve 206 c in the direction of flow of the oil in the communication hole 206 b. The orifice 206 d is a throttle mechanism for adjusting the amount of oil supplied from the oil storing chamber 206 a to the refrigerant pump 205 to an appropriate amount.

In this embodiment, the orifice 206 d is formed on the downstream side of the check valve 206 c in the direction of flow of oil but may be formed on the upstream side of the check valve 206 c. In this embodiment, an orifice having a minimum opening diameter of 0.5 mm is used to realize the proper amount of oil supplied to the refrigerant pump 205.

Next, the refrigerant pump 205 will be described. The refrigerant pump 205 is arranged on the most downstream portion of the fluid machine 202 integrated with an expander and is refrigerant pressure-feeding means provided with a mechanism for pressure-feeding the refrigerant. In this embodiment, the refrigerant pressure-feeding mechanism of the refrigerant pump 205 can have the same structure as the publicly known scroll type compression mechanism.

Specifically, the refrigerant pump 205 includes: a lower housing 501, the coupling part housing 403; the pump shaft 502; a fixed scroll (shell) 503 that is a fixed part integral with the lower housing 501; a revolving scroll 504 (movable scroll) that is a moving member revolving and shifting in position in a space between the coupling part housing 403 and the fixed scroll 503; an operating chamber 505 that feeds the refrigerant in a space between the fixed scroll 503 and the revolving scroll 504; a refrigerant suction port 205 a which communicates with the operating chamber 505 and from which the refrigerant is sucked; a refrigerant discharge port 205 b which communicates with the operating chamber 505 and from which the refrigerant is discharged; and the like.

The lower housing 501 and the coupling part housing 403 act as protecting members for protecting the refrigerant pump 205. The lower housing 501 is integrally constructed of the fixed scroll 503, and has the refrigerant discharge port 205 b and the refrigerant suction port 205 a. Moreover, the lower housing 501 and the coupling part housing 403 are coupled to each other by screws via sealing members such as gasket and O-ring to prevent the refrigerant from leaking from the coupled portion. In addition, the coupling part housing 403 is common to the constituent parts of the driving and electric-power generating part 204 so as to reduce the size of the fluid machine.

The pump shaft 502 is supported by the coupling part housing 403 via a ball bearing 506. The pump shaft 502 is coupled to the shaft 303 by a one-way clutch 507. The one-way clutch is power transmitting means that has the function of transmitting the rotational driving force of the shaft 303 to the pump shaft 502 only in the expander mode.

Moreover, the pump shaft 502 is a crankshaft having an eccentric part 508 that is eccentric with respect to the rotational central axis on the lower end side in the axial direction. The revolving scroll 504 is rotatably coupled to the eccentric part 508 via a needle bearing.

The fixed scroll 503 is constructed of a plate-shaped base plate part 503 a and a spiral tooth part 503 b that protrudes from the base plate part 503 a toward the coupled part housing 403 (in the up direction). Meanwhile, the revolving scroll 504 is constructed of a spiral tooth part 504 b that is contact with and is engaged with the tooth part 503 b of the fixed scroll 503 and the base plate part 504 a having the tooth part 504 b formed thereon.

Moreover, a rotation preventing mechanism (not shown) is interposed between the revolving scroll 504 and the coupling part housing 403. The rotation preventing mechanism causes the revolving scroll 504 to revolve around the eccentric part 508 one revolution while the pump shaft 502 rotates one rotation. When the pump shaft 502 rotates, the revolving scroll 504 does not rotate but revolves around the rotational central axis of the pump shaft 502. The rotation preventing mechanism in this embodiment employs the same pin-ring (pin-hole) type mechanism as the compression and expansion part 203.

The refrigerant suction port 205 a is a suction port of the liquid-phase refrigerant made in the outer peripheral portion of the lower housing 501 and communicates with the outermost diameter portion of the operating chamber 505. The refrigerant discharge port 205 b is the discharge port of the refrigerant made in the lower portion of the lower housing 501 and is made at a position communicating with the operating chamber 505.

Next, an oil supply passage 206 will be described. The oil supply passage 206, as shown by the arrow in FIG. 13, is so constructed as to communicate in the order of: the low-pressure port 203 a→the space between the middle housing 302 and the revolving scroll 305→the space in the ball bearing 307→the oil storing chamber 206 a→the communication hole 206 b→the space in the ball bearing 405→the space in the ball bearing 506→the space between the coupling part housing 403 and the revolving scroll 504→the refrigerant suction port 205 a.

Next, the operation of the vapor compression type refrigerator in this embodiment will be described. First, in the compressor mode, the control unit 21 supplies the driving and electric-power generating part 204 with electric power and opens the open/close valve 218 and causes the control valve 219 to function as a check valve and switches the three-way valve 216 to the bypass passage of the heater 213.

When the driving and electric-power generating part 204 is supplied with electric power, the shaft 303 coupled to the rotor 402 rotates to apply a rotational driving force to the compression and expansion part 203. Here, in the compression and expansion part 203, when the revolving scroll 305 revolves in one direction with respect to the fixed scroll 304, the volume of the operating chamber 306 is decreased; and when the revolving scroll 305 revolves in a reverse direction, the volume of the operating chamber 306 is increased. Hence, the rotational direction of this rotational driving force becomes a direction to decrease the volume of the operating chamber 306 (hereinafter referred to as “compression direction”). Therefore, in the compressor mode, the refrigerant sucked from the low-pressure port 203 a flows into the operating chamber 306 and is compressed in the operating chamber 306 and is discharged from the high-pressure port 203 b.

Here, a part of vapor-phase refrigerant sucked from the low-pressure port 203 a flows into the oil storing chamber 206 a communicating with the low-pressure port 203 a. Since the refrigerant is mixed with oil for lubricating the mechanical sliding parts, the oil also flows into the oil storing chamber 206 a along with the vapor-phase refrigerant. Since this oil has a larger specific gravity than the vapor-phase refrigerant, the oil is separated from the vapor-phase refrigerant by the gravity and is moved below and is stored in the lowermost portion of the oil storing chamber 206 a. A wavy line 407 in FIG. 13 shows the level of oil stored at the time of a normal operation.

When the oil storing chamber 206 a is filled with the oil and the oil level goes up as shown by a wavy line 407 a in FIG. 13, the vapor-phase refrigerant is hard to flow into the oil storing chamber 206 a and hence the oil is hard to separate, which results in being able to prevent the oil from being separated from the refrigerant more than necessary. Furthermore, the oil stored in the oil storing chamber 206 a exists in the same space as the stator 401 and the rotor 402 and hence also produces the effect of cooling the driving and electric-power generating part 204.

The refrigerant discharged from the high-pressure port 203 b is pressure-fed to the radiator 207 through the control valve 219, the heater 213, and the open/close valve 218. Here, in the compressor mode, the open/close valve 218 is opened and the three-way valve 216 is switched to the bypass passage of the heater 213 and hence the engine cooling water in the hot water circuit 214 bypasses the heater 213 and circulates in the order of: the water pump 215→the engine 201→the three-way valve 216→the radiator 217→the water pump 215. Hence, the refrigerant is not heated, and the heater 213 and the open/close valve 218 function only as refrigerant passages.

The refrigerant having heat radiated by the radiator 207 is separated into the vapor-phase refrigerant and the liquid-phase refrigerant by the vapor-liquid separator 209. Here, in the compressor mode, the refrigerant pump 205 is not operated and hence the liquid-phase refrigerant in the vapor-liquid separator 209 is not sucked into the refrigerant pump 205.

The liquid-phase refrigerant separated by the vapor-liquid separator 209 has pressure reduced by the expansion valve 211 and absorbs heat in the evaporator 212 and is sucked from the low-pressure port 203 a of the fluid machine 202 integrated with an expander.

With this, in the compressor mode, the refrigerant can be circulated in the order of: the fluid machine 202 integrated with an expander→the radiator 207→the vapor-liquid separator 209→the expansion valve 211→the evaporator 212→the fluid machine 202 integrated with an expander. Hence, a vapor compression type refrigerator can be constructed, which moves heat absorbed by the evaporator 212 to the radiator 207 to thereby radiate the heat.

Here, the back pressure on the oil storing chamber 206 a side is the same as the pressure at the low-pressure port 203 a but the back pressure on the refrigerant suction port 205 a side is higher than the pressure at the low-pressure port 203 a because the refrigerant suction port 205 a communicates with the vapor-liquid separator 209. When this pressure difference makes the refrigerant in the vapor-liquid separator 209 flow reversely to the oil storing chamber 206 a via the oil supply passage 206, the high-pressure refrigerant is again sucked into the low-pressure port 203 a to cause a reduction in the refrigeration capacity of the vapor compression type refrigerator. Hence, in this embodiment, the check valve 206 c prevents the backflow of the refrigerant.

Next, in the expander mode, the control unit 221 connects the driving and electric-power generating part 204 to the power storage battery 222, closes the open/close valve 218, opens the control valve 219, and switches the three-way valve 216 to the heater 213.

When the three-way valve 216 is switched to the heater 213, the engine cooling water in the hot water circuit 214 is circulated in the order of: the water pump 215→the engine 201→the heater 213→the three-way valve 216→the radiator 217→the water pump 215. Hence, the refrigerant in the heater 213 is heated by the waste heat of the engine 201. The heated refrigerant flows out from the heater 213 to the high-pressure port 203 b through the control valve 219 and flows from the high-pressure port 203 b into the operating chamber 306 of the compression and expansion part 203.

The refrigerant flowing into the operating chamber 306 is evaporated and expanded to expand the volume of the operating chamber 306 to thereby rotate the revolving scroll 305 and the shaft 303 in the direction for expanding the volume of the operating chamber 306 (hereinafter referred to as “expansion direction”). The expanded refrigerant flows out from the low-pressure port 203 a.

This rotation rotates also the rotor 402 coupled to the shaft 303 to change the amount of magnetic flux passing through the coil of the stator 401 to thereby operate the driving and electric-power generating part 204 as a generator. The generated electric power is stored in the electric power storage battery 222 connected to the driving and electric-power generating part 204 via the control unit 221. That is, the waste heat of the engine 201 expands the refrigerant. The expanded refrigerant causes the fluid machine 202 integrated with an expander to output mechanical energy. The mechanical energy is converted to electric energy by the driving and electric-power generating part 204. In this manner, thermal energy is recovered.

Furthermore, a part of this mechanical energy is transmitted as the driving force of the refrigerant pump 205 to the pump shaft 502 via the one-way clutch 507. Here, in the refrigerant pump 205, when the pump shaft 502 rotates in the expansion direction, the revolving scroll 504 revolves with respect to the fixed scroll 503 and hence the operating chamber 505 moves from a position communicating with the refrigerant suction port 205 a to the refrigerant discharge port 205 b. Hence, in the expander mode, the liquid-phase refrigerant sucked from the refrigerant suction port 205 a is pressure-fed from the refrigerant discharge port 205 b to the heater 213 and the pressure-fed refrigerant is heated and expanded so that the compression and expansion part 203 can output more mechanical energy.

The compression rate of scroll type compression mechanism of the refrigerant pump 205 is one. Accordingly, even when the liquid-phase refrigerant is sucked into the operating chamber 505, the liquid-phase refrigerant is not compressed so that the refrigerant pump 205 does not produce any operation trouble resulting from liquid compression. In the compressor mode, the driving force is not transmitted to the refrigerant pump 205 by the one-way clutch 507 and hence the refrigerant pump 205 is not operated.

Meanwhile, the refrigerant flowing out from the low-pressure port 203 a passes through the second bypass passage 220 by the function of the check valve 212 a and radiates heat by the radiator 207 and moves to the vapor-liquid separator 209. Here, a part of refrigerant flowing out from the low-pressure port 203 a flows into the oil storing chamber 206 a. Accordingly, just as with the compressor mode, oil is separated and stored in the oil storing chamber 206 a.

With this, in the expander mode, the refrigerant can be circulated in the order of: the refrigerant pump 205→the heater 213→the fluid machine 202 integrated with an expander→the second bypass passage 220→the radiator 207→the vapor-liquid separator 209→the first bypass passage 210→the refrigerant pump 205. In this manner, when the refrigerant is expanded by heat absorbed in the heater 213, mechanical energy can be produced by the fluid machine 202 integrated with an expander to thereby construct the Ranking cycle.

Here, the back pressure on the oil storing chamber 206 a side is the same as the pressure at the low-pressure port 203 a. The back pressure on the refrigerant suction port 205 a side is made lower than the pressure at the low-pressure port 203 a by a pressure loss caused when the refrigerant passes through the radiator 207 and the refrigerant piping and the negative pressure caused by suction of the refrigerant pump 205.

By this pressure difference, the oil stored in the oil storing chamber 206 a is supplied to the refrigerant suction port 205 a of the refrigerant pump 205 via the oil supply passage 206. This oil has a property easily dissolving in the liquid-phase refrigerant. However, because the distance from the refrigerant suction port 205 a to the mechanical sliding parts is short and a sufficient amount of oil can be supplied to the mechanical sliding parts, the oil can reach to the mechanical sliding parts before the oil fully dissolves in the liquid-phase refrigerant. Therefore, the oil can sufficiently lubricate the mechanical sliding parts.

Ninth Embodiment

In the above-described eighth embodiment, the fluid machine 202 integrated with an expander has been described in which the check valve 206 c and the orifice 206 d are set in the communication hole 206 b of the lubricating oil. In this embodiment, however, as shown by cross-sectional view in FIG. 14, only the orifice 206 d is formed in the communication hole 206 b but the check valve 206 c is not set. The other construction is the same as in the eighth embodiment.

When the fluid machine 202 integrated with an expander is operated in the compressor mode, the refrigerant flows back to the oil storing chamber 206 a via the communication hole 206 b by the pressure difference between the back pressure on the oil storing chamber 206 a side and the back pressure on the suction port 205 a side. However, a reduction in the refrigeration capacity of the vapor compression type refrigerator caused by this backflow can be allowed when the reduction is as small as a degree not to degrade the air-conditioning function for the vehicle.

Hence, the passage resistance of the oil supply passage 206 is adjusted by the orifice 206 d, spaces in the ball bearings 405 and 506, and the space between the coupling part housing 403 and the revolving scroll 504, which construct the oil supply passage 206, to make the determination of the amount of supply of the oil be compatible with the limitation of amount of backflow of the refrigerant. This can produce the same effect as the eighth embodiment even when the check valve 206 c is not set.

Tenth Embodiment

In the eighth and ninth embodiments, the communication hole 206 b is made in the coupling part housing 403 to construct the oil supply passage 206. In this embodiment, however, in place of the oil supply passage 206, as shown by the cross-sectional view in FIG. 15, a communication hole 261 b having an orifice 261 d is formed in the lower end side of the shaft 303 to construct the oil supply passage 261. The other construction is the same as that in the ninth embodiment.

Even when the communication hole 261 b is formed in the lower end side of the shaft 303, there is produced the same effect as the ninth embodiment. Furthermore, the oil supply passage 261, as shown by arrow in FIG. 16, is so constructed as to communicate in the order of: the low-pressure port 203 a→the space between the middle housing 302 and the revolving scroll 305→the space in the ball bearing 307→the oil storing chamber 206 a→the communication hole 261 b→the space in the one-way-clutch 507→the space in the ball bearing 506→the space between the coupling part housing 403 and the revolving scroll 504→the refrigerant suction port 205 a. Hence, the refrigerant can lubricate the mechanical sliding parts of the one-way-clutch 507.

Eleventh Embodiment

In the eighth, ninth, and tenth embodiments, there has been provided the description of the vapor compression type refrigerator using the fluid machine 202 integrated with an expander that is integrally constructed of the compression and expansion part 203, the driving and electric-power generating part 204, the refrigerant pump 205, and the oil supply passage 206. In this embodiment, however, as shown by a general construction diagram in FIG. 17, the refrigerant pump 205 and oil supply piping 262 are constructed as separate parts and the fluid machine 202 integrated with an expander is not integrally constructed of the refrigerant pump 205 and the oil supply passage 206.

The refrigerant pump 205 is an electrically driven pump mounted in the vehicle engine room and is supplied with electric power from the control unit 221 only in the expander mode, thereby being operated. Hence, this embodiment is not provided with the power transmitting means for transmitting the driving power from the compression and expansion part 203. However, when this refrigerant pump 205 is operated only in the expander mode, a pump may be used which receives driving power from the engine 201 or the compression and expansion part 203 via the power transmitting means, thereby being operated.

The oil supply passage 262 is piping for connecting the low-pressure port 203 a to the refrigerant suction port 205 a and is communication means in this embodiment. The oil supply passage 262 is provided with a check valve 262 c for allowing the oil to flow from an oil tank 262 a and the low-pressure port 203 a only to the refrigerant suction port 205 a, and an orifice 262 d of a throttle mechanism for adjusting the amount of oil on the downstream side of the check valve 262 c in the direction of oil.

The oil tank 262 a is a tank having the function of a receiver that has a space and separates the lubricating oil from the refrigerant by the gravity and stores the lubricating oil. The oil tank 262 a is oil storing means in this embodiment. The other construction is the same as in the eighth embodiment.

In the above-described construction, in the compressor mode, the control unit 221 does not supply the refrigerant pump 205 with electric power and hence the same vapor compression type refrigerator as in the first embodiment is constructed. In the expander mode, the control unit 221 supplies the refrigerant pump 205 with electric power and hence the same Rankine cycle as in the first embodiment is constructed.

Hence, even when the refrigerant pump 205 and the oil supply piping 262 are constructed separately from the fluid machine 202 integrated with an expander, the oil stored in the oil tank 262 a is supplied to the refrigerant suction port 205 a by the pressure difference between the low-pressure port 203 a and the refrigerant suction port 205 a and hence can sufficiently lubricate the mechanical sliding parts of the refrigerant pump 205.

Twelfth Embodiment

In the above-described eighth to eleventh embodiments, the vapor compression type refrigerator combined with the Rankine cycle has been described. In this embodiment, however, a refrigerator designed specifically for the Rankin cycle will be described.

FIG. 18 is a schematic diagram showing an entire cycle construction of a refrigerator designed specifically for the Rankin cycle of recovering the waste heat of the vehicle engine 201. First, the fluid machine 202 functioning as an expander has the same construction as in the eighth embodiment. However, the compression and expansion part 203 in the eighth embodiment functions only as expansion means for outputting mechanical energy by the expansion of the refrigerant, and the driving and electric-power generating part 204 functions only as power generating means for generating electric power by the mechanical energy.

In the refrigerator designed specifically for the Rankin cycle, the fluid machine 202 does not operate as a compressor and hence the shaft 303 rotates only in the expansion direction described above. Hence, the shaft 303 may be coupled to the pump shaft 502 so as to rotate integrally with each other without using the one-way clutch 507.

Next, a radiator 270 radiates heat of the refrigerant to cool the refrigerant. The refrigerant inlet of the radiator 270 is connected to the low-pressure port 203 a of the fluid machine 202 by refrigerant piping. A vapor-liquid separator 290 is a receiver for separating the refrigerant flowing out from the radiator 270 into the vapor-phase refrigerant and the liquid-phase refrigerant.

The liquid-phase refrigerant side of the vapor-liquid separator 290 and the refrigerant suction port 205 a of the refrigerant pump 205 are coupled to each other by refrigerant piping so as to supply the separated liquid-phase refrigerant to the refrigerant suction port 205 a. The refrigerant discharge port 205 b of the refrigerant pump 205 is coupled to the heater 213.

The heater 213 is a heat exchanger that exchanges the refrigerant pressure-fed from the refrigerant pump 205 for the engine cooling water to thereby heat the refrigerant. The engine cooling water is circulated through the same hot water circuit 214 as in the eighth embodiment. The refrigerant outlet of the heater 213 is coupled to the high-pressure port 203 b of the fluid machine 202 by the refrigerant piping.

The control unit 221 connects the electric power generating means to the electric power storage battery 222 and performs the control of switching the three-way valve 216.

In the above-described construction, the control unit 221 connects the electric power generating means to the electric power storage battery 222 and switches the three-way valve 216 to the heater 213 to construct a Rankin cycle of circulating the refrigerant in the order of: the heater 213→the fluid machine 202 integrated with an expander→the radiator 270→the vapor-liquid separator 290→the refrigerant pump 205→the heater 213. In the manner, just as with the eighth embodiment, electric energy can be stored in the electric power storage battery 222.

Furthermore, just as with the eighth embodiment, the oil stored in the oil storing chamber 206 a can be supplied to the refrigerant suction port 205 a of the refrigerant pump 205 via the oil supply passage and hence can sufficiently lubricate the mechanical sliding parts of the refrigerant pump 205.

Thirteenth embodiment

The thirteenth embodiment uses a fluid machine 200 shown in FIG. 19 in place of the vapor compression type fluid machine 202 integrated with an expander in the twelfth embodiment. The thirteenth embodiment is the same in the other construction as the twelfth embodiment. FIG. 19 is a cross-sectional view of the fluid machine 200. In FIG. 19, parts having the same or equivalent functions as those in the above-described eighth embodiment are denoted by the same reference symbols.

The fluid machine 200 is constructed of an expansion part 203′, an electric power generating part 204′, a refrigerant pump 251, an oil passage 263, and the like. In the fluid machine 200, parts are arranged in order of the refrigerant pump 251, the electric power generating part 204′, the expansion part 203′ from the upstream side, which is reverse to the order of arrangement of parts in the fluid machine 202 integrated with an expander in the eighth embodiment.

The basic construction of the expansion part 203′ is the same as that in the eighth embodiment but is different in the arrangement of the low-pressure port 203 a. In this embodiment, the low-pressure port 203 a is formed in the outer peripheral portion of the middle housing 302.

In the middle housing 302, a low-pressure refrigerant communication passage 302 a that communicates with a low-pressure refrigerant outflow port 301 a of the housing 301 of the expansion part 203′ and introduces refrigerant after expansion into the middle housing 302 is formed in the outer peripheral portion of the middle housing 302 in such a way as to extend in the up and down direction.

The low-pressure port 203 a is formed at a position that is nearly symmetric to the upper end of the low-pressure refrigerant passage 302 a with respect to the central axis of the shaft 303.

The basic construction of the electric power generating part 204′ is the same as the electric power generating part 204 in the eighth embodiment but is different in that the low-pressure refrigerant flowing through the low-pressure refrigerant passage 302 a passes through an internal space in the middle housing 302, in which the stator 401 and the rotor 402 are arranged, and reaches the low-pressure port 203 a.

The refrigerant pump 251 is refrigerant pressure-feeding means that pressure-feeds a liquid-phase refrigerant to the expansion part 203′ at the time of recovering thermal energy and employs a publicly-known rolling piston type pressure-feeding mechanism as a pressure-feeding mechanism in this embodiment.

FIG. 20 is a cross-sectional view taken on the line XX-XX in FIG. 19. FIG. 21 is a cross-sectional view taken on the line XXI-XXI in FIG. 20. The refrigerant pump 251 includes a pump housing 511, the coupling part housing 403, a pump shaft 512, a front plate 513, a rear plate 514, a cylinder 515, a pump rotor 516, and the like. The pump housing 511 has a refrigerant discharge port 205 b and a refrigerant suction port 205 a.

The pump shaft 512 is rotatably supported by the front plate 513 and the rear plate 514 via a ball bearing 517 and is a crankshaft having an eccentric portion 518. The pump rotor 516 is rotatably coupled to the eccentric portion 518.

The cylinder 515 is sandwiched from above and below by the front plate 513 and the rear plate 514 and has an operating space, in which the pump rotor 516 operates, formed on the inner peripheral side.

The rear plate 514 has a refrigerant suction passage 514 a for introducing refrigerant flowing from the suction port 205 a into the hosing 511 to the operating space.

The front plate 513 has a refrigerant discharge passage 513 a for introducing refrigerant in the operating space to the refrigerant discharge port 205 b. At the exit of the refrigerant discharge passage 513 a, a reed valve is provided as a check valve 513 b that allows the refrigerant to flow only to the refrigerant discharge port 205 b.

Moreover, the front plate 513 has a suction-side communication passage 513 c that makes the refrigerant suction port 205 a communicate with a mechanical sliding part B (specifically, space where the eccentric part 518 is arranged). This suction-side communication passage 513 c applies pressure on the suction side of the refrigerant pump 251 to the mechanical sliding part B to make the back pressure of the mechanical sliding part B equal to the pressure of the refrigerant suction port 205 a.

The pump rotor 516 has a sliding bearing 519 on the inner peripheral portion to become a portion coupled to the eccentric part 518. The amount of clearance between the outside diameter of the eccentric part 518 and the inside diameter of the sliding bearing 519 is approximately from 20 μm to 40 μm.

A vane 515 c that is always pressed onto the outer peripheral surface of the pump rotor 516 by a spring 515 b is arranged in a cut portion 515 a on the inner peripheral side of the cylinder 515.

Moreover, the cylinder 515 has a refrigerant suction port 515 d communicating with the refrigerant suction passage 514 a and a refrigerant discharge port 515 e communicating with the refrigerant discharge passage 513 a.

The section of the refrigerant pump 251 shown in FIG. 19 shows a cross-sectional view taken on the line XXI-XXI in FIG. 20 for the sake of convenience in showing the refrigerant suction portion 515 d and the refrigerant discharge port 515 e.

The pump shaft 512 protrudes to the coupling part housing 403 (lower side in FIG. 19) and is coupled to the shaft 303. Here, the shaft 303 may be coupled to the pump shaft 512 by the use of transmission means (for example, one-way clutch) capable of transmitting a driving force from the shaft 303 to the pump shaft 512 only when the expansion part 203′ outputs mechanical energy. Moreover, a lip seal 406 is interposed between the pump shaft 512 and the coupling part housing 403 to seal therebetween. Here, a seal member having other structure can be used for the sealing, instead of the lip seal 406. Furthermore, the pump shaft 512 has an oil communication hole 520 that makes the end of the coupling part housing 403 communicate with the mechanical sliding part B.

Next, an oil supply passage 263 will be described. The oil supply passage 263 is communication means for making the low-pressure port 203 a communicate with the mechanical sliding part B. In this embodiment, the oil supply passage 263 is constructed in such a way that oil separated from the vapor-phase refrigerant, which collides with the stator 401 and the rotor 402 of the power generating part 204′ arranged in the middle housing 302 when the vapor-phase refrigerant flowing out of the low-pressure refrigerant outflow port 301 a moves to the low-pressure port 203 a, is stored in an oil storing chamber 263 a and, as shown by arrow in FIG. 19, flows from the oil storing chamber 263 a in order of the oil communication passage 303 a of the shaft 303→the check valve 263 c→the communication hole 520 of the pump shaft 512→the mechanical sliding part B. Here, a pressure in the oil storing chamber 263 a is equal to a pressure at the low-pressure port 203 a, and a back pressure on the mechanical sliding part B is equal to the pressure of refrigerant on the refrigerant suction port 205 a side because the suction side communication passage 513 c is formed. Further, the pressure of refrigerant on the refrigerant suction port 205 a side is made lower than the pressure at the low-pressure port 203 a by a pressure loss caused when the refrigerant passes through the heat radiator 270 and refrigerant piping and negative pressure caused by the suction of the refrigerant pump 205. For this reason, the oil stored in the oil storing chamber 263 a is supplied to the mechanical sliding part B of the refrigerant pump 251 via the oil supply passage 263 by this pressure difference.

By the way, in this embodiment, in order to rotate the pump rotor 516, clearances of from 5 μm to 20 μm are formed between the front plate 513 and the pump rotor 516 and between the rear plate 514 and the pump rotor 516, respectively. For this reason, the liquid-phase refrigerant may flow from the refrigerant pressure-feeding space to the mechanical sliding part B through the clearances between the front plate 513 and the pump rotor 516 and between the rear plate 514 and the pump rotor 516 (this liquid-phase refrigerant flowing to the mechanical sliding part B is hereinafter referred to as “leakage refrigerant”). When the leakage refrigerant flows into the mechanical sliding part B, it is also thought that the oil supplied from the oil supply passage 263 to the mechanical sliding part B dissolves in the leakage refrigerant and hence cannot sufficiently lubricate the mechanical sliding part B.

Hence, the present inventors studied the appropriate amount of supply of oil with respect to the flow rate of leakage refrigerant flowing into the mechanical sliding part B. As a result, the inventors found that when the flow rate of supply of oil was not less than 30% of the flow rate of liquid-phase refrigerant with respect to the flow rate (flow rate of mass) of leakage refrigerant flowing into the mechanical sliding part B, the oil can sufficiently lubricate the mechanical sliding part B. Therefore, in this embodiment, the amount of clearance between the outside diameter of the eccentric part 518 and the inside diameter of the sliding bearing 519 is set at a value of approximately from 20 μm to 40 μm to thereby make the amount of supply of oil supply not less than 30% of the flow rate of liquid-phase refrigerant with reliability.

Because the clearance between the front plate 523 and the pump rotor 516 is extremely small (for example, from 5 μm to 20 μm) in the thirteenth embodiment, when the leakage refrigerant and the oil pass through this clearance, a pressure loss develops. Hence, it is also recommendable to form a suction side communication passage, which makes the suction side of the refrigerant pump 251 communicate with the clearance between the front plate 523 and the pump rotor 516, in the front plate 523 or the rear plate 514. With this, the leakage refrigerant passes from the refrigerant pressure-feeding space to the suction side communication passage through the clearance between the front plate 513 and the pump rotor 516 and is hard to flow into the mechanical sliding part B.

Moreover, a single or a plurality of through holes may be formed in both surfaces (upper and lower surfaces) of the pump rotor 516.

In the thirteenth embodiment has been shown an example in which the fluid machine 200 is applied to an apparatus designed specifically for a Rankin cycle. However, the fluid machine 200 may be applied to a vapor compression type refrigerator combined with a Rankin cycle by the use of a transmission mechanism (for example, one-way clutch) capable of transmitting a driving force from the shaft 303 to the pump shaft 512 only when the expansion part 203′ outputs mechanical energy.

Moreover, the apparatus designed specifically for a Rankin cycle in which the fluid machine 200 integrally constructed of the expansion part 203′, the driving and power generating part 204′, the refrigerant pump 251, and the oil supply passage 263 has been described in the thirteenth embodiment. However, similarly to the eleventh embodiment, the refrigerant pump and the oil supply piping may be constructed separately. In this case, when the oil flows from the oil supply piping to the communication hole 520 of the pump shaft 512, just as with the thirteenth embodiment, the oil can sufficiently lubricate the mechanical sliding part B.

Furthermore, in the thirteenth embodiment, specifically, the mechanical sliding part B is constructed of the eccentric part 518 and the sliding part of the sliding bearing 519, but the mechanical sliding part B is not limited to this.

Other Embodiments

Although the present invention has been fully described in connection with the preferred embodiments thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications will become apparent to those skilled in the art.

For example, in the above-described second embodiment having the back pressure chamber 116, the movable scroll 113 may have multiple small-diameter holes for adjusting the pressure between the operating chamber V and the back pressure chamber 116 in addition to the small-diameter passage 113 c. The small-diameter holes make the back pressure chamber 116 communicate with the suction side (low-pressure side) of the operating chamber V. With this, when the pressure in the back pressure chamber 116 is excessively increased, the small-diameter holes cause the pressure to leak from the back pressure chamber 116 to the operating chamber V, so as to prevent an excessive increase in the back pressure. Moreover, the small-diameter hole may be provided with a mechanism for feeding the liquid refrigerant to the low pressure side before the back pressure excessively increases. For example, the small-diameter hole may be provided with a safety valve acting as this mechanism. For example, a ball type valve, a valve to be backed up by a spring, a ball spring type valve can be used as the safety valve.

Furthermore, the present invention can be applied to a liquid pump for pressure-feeding fluid such as a positive-displacement pump including a scroll type pump and a rotary vane type pump. In addition, the above-described first to seventh embodiments can be suitably combined.

In the above-described eighth to eleventh embodiments, the compression and expansion part 203 is supplied with the rotational driving power from the driving and electric-power generating part 204, thereby being driven. However, the compression and expansion part 203 may be supplied with the rotational driving power from the engine 201 by the use of a power transmitting mechanism constructed of an electromagnetic clutch, a pulley, and a belt.

Moreover, in the above-described eighth to twelfth embodiments, the scroll type pump mechanism is employed for the compression and expansion part (expansion means) 203 and the refrigerant pump 205. However, other type compression and expansion mechanism such as rotary type, piston type, and vane type may be employed.

Further, in the above-described eighth to twelfth embodiments, energy recovered by the fluid machine 202 integrated with an expander is stored as electric energy in the electric power storage battery 222. However, the energy may be stored as kinetic energy by the use of a flywheel or mechanical energy such as elastic energy by the use of a spring. In addition, the above-described recovered energy may be used in order to assist the rotational driving power of the engine 201.

Still further, in the above-described embodiments, the oil is separated from the refrigerant only by the use of the gravity. It is also recommendable to form the refrigerant passage in a circular shape and to separate the oil from the refrigerant by the use of centrifugal force.

Such changes and modifications are to be understood as being within the scope of the present invention as defined by the appended claims. 

1. A fluid pump comprising: a driving part; a movable part that is movable by power transmitted from the driving part; a transmission part through which the power from the driving part is transmitted to the movable part; a fixed part disposed on a side of the movable part, opposite to the transmission part, to form an operating chamber having an outlet from which a fluid flowing into the operating chamber is pressure-fed to an outside in a liquid state by the movable part; and an introduction passage for introducing a part of the fluid in the operating chamber to the transmission part.
 2. The fluid pump according to claim 1, wherein: the introduction passage is provided in the movable part; and the introduction passage has an opening part opened to the operating chamber to be tapered.
 3. The fluid pump according to claim 1, wherein: the movable part includes a passage part for defining the introduction passage; and the passage part is a member separate from the movable part.
 4. The fluid pump according to claim 1, wherein: the movable part is a movable scroll having a base plate portion and a first wall portion protruding from the base plate portion in a spiral shape; the fixed part is a fixed scroll having a spiral second wall portion engaged with the first wall portion; and the introduction passage has a diameter smaller than a predetermined value, and is provided in the base plate portion of the movable scroll to make the operating chamber communicate with the transmission part at a predetermined pressure loss.
 5. The fluid pump according to claim 4, wherein: the transmission part is housed in a closed space; and the movable scroll receives a back pressure applied thereto on a side of the fixed scroll by the fluid introduced into the closed space.
 6. The fluid pump according to claim 5, wherein: the movable scroll has a plurality of holes, each having a diameter smaller than a predetermined value, for adjusting pressure between the operating chamber and the closed space.
 7. The fluid pump according to claim 1, wherein: the movable part is a rotor that is made to revolve by the driving part arranged in a center of the movable part; the fixed part is a cylinder housing in which a cylinder housing the rotor is disposed; and the introduction passage is a passage having a diameter smaller than a predetermined value, and is provided in the rotor to make the operating chamber communicate with the transmission part at a predetermined pressure loss.
 8. The fluid pump according to claim 1, wherein: the movable part is a rotor that is revolve by the driving part arranged in a center of the movable part; the fixed part is a cylinder housing in which a cylinder housing the rotor is disposed; and the introduction passage is a groove that is provided on an end surface in an axial direction of the rotor and makes the operating chamber communicate with the transmission part at a predetermined pressure loss.
 9. A fluid machine comprising: an expansion member having a function of outputting mechanical energy by expansion of refrigerant, the expansion member having a low-pressure port from which low-pressure vapor-phase refrigerant after being decompressed flows out and a high-pressure port from which high-pressure refrigerant before being decompressed flows in; an electric power generating member having a function of generating electric power by using the mechanical energy; a refrigerant pressure-feeding member for pressure-feeding refrigerant to the expansion member, the refrigerant pressure-feeding member having a refrigerant suction port from which liquid-phase refrigerant is sucked and a refrigerant discharge port from which liquid-phase refrigerant is discharged; and a communication part for making the low-pressure port of the expansion member communicate with the refrigerant suction port of the refrigerant pressure-feeding member, wherein the communication part separates lubricating oil from vapor-phase refrigerant and supplies the lubricating oil to the refrigerant suction port.
 10. The fluid machine according to claim 9, further comprising a housing which houses all of the expansion member, the electric power generating member and the refrigerant pressure-feeding member.
 11. The fluid machine according to claim 9, wherein the low-pressure port is arranged above the refrigerant suction port.
 12. The fluid machine according to claim 9, wherein: the expansion member having the low-pressure port that is arranged above the electric power generating member; and the refrigerant pressure-feeding member having the refrigerant suction port is arranged below the electric power generating member.
 13. The fluid machine according to claim 9, wherein: the communication part separates the oil from the vapor-phase refrigerant by gravity by the use of a difference in specific gravity between the vapor-phase refrigerant and the oil and includes an oil storing part for storing the separated oil.
 14. The fluid machine according to claim 13, wherein the oil storing part is provided in the electric power generating member.
 15. The fluid machine according to claim 9, wherein the communication part has a check valve for preventing the liquid-phase refrigerant from flowing back from the refrigerant suction port to the low-pressure port.
 16. The fluid machine according to claim 15, wherein: the communication part has a throttle mechanism connected in series to the check valve; and the throttle mechanism has a refrigerant passage area smaller than a refrigerant passage area of the check valve.
 17. The fluid machine according to claim 9, further comprising a transmission part for transmitting driving power from the expansion member to the refrigerant pressure-feeding member, wherein the refrigerant pressure-feeding member is operated by the driving power from the expansion member.
 18. The fluid machine according to claim 17, wherein the transmission part is a one-way clutch that transmits the mechanical energy as the driving power from the expansion member only when the expansion member outputs the mechanical energy.
 19. The fluid machine according to claim 9, wherein: the expansion member is a compression and expansion member that has a function of compressing refrigerant by driving power applied thereto; the electric power generating member is a driving and electric-power generating member that applies the driving power to the compression and expansion member; and when the compression and expansion member compresses refrigerant, the low-pressure port sucks low-pressure vapor-phase refrigerant after being decompressed and the high-pressure port discharges high-pressure refrigerant before being decompressed.
 20. A fluid machine comprising: an expansion member having a function of outputting mechanical energy by expansion of refrigerant; a refrigerant pressure-feeding member for pressure-feeding refrigerant to the expansion member, the expansion member having a low-pressure port from which low-pressure vapor-phase refrigerant after being decompressed flows out and a high-pressure port from which high-pressure refrigerant after being decompressed flows in; and a communication part that introduces oil contained in refrigerant flowing out from the low-pressure port to a sliding part of the refrigerant pressure-feeding member.
 21. A vapor compression type refrigerator combined with a Rankine cycle, comprising: a compression and expansion member that has a function of compressing and discharging refrigerant by driving power applied thereto and a function of outputting mechanical energy by expansion of refrigerant, the compression and expansion member having a low-pressure port from which low-pressure refrigerant after being decompressed is sucked and flows out and a high-pressure port from which high-pressure refrigerant before being decompressed is discharged and flows in; a driving and electric-power generating member that has a function of applying the driving power to the compression and expansion member and a function of generating electric power by the mechanical energy; a refrigerant pressure-feeding member that pressure-feeds refrigerant to the compression and expansion member, the refrigerant pressure-feeding member having a refrigerant suction port from which liquid-phase refrigerant is sucked and a refrigerant discharge port from which liquid-phase refrigerant is discharged; and a communication part that makes the low-pressure port communicate with the refrigerant suction port, wherein the communication part separates lubricating oil from the vapor-phase refrigerant and supplying the lubricating oil to the refrigerant suction port.
 22. A vapor compression type refrigerator combined with a Rankine cycle, comprising: a compression and expansion member that has a function of compressing and discharging refrigerant by driving power applied thereto and a function of outputting mechanical energy by expansion of refrigerant, the compression and expansion member having a low-pressure port from which low-pressure refrigerant after being decompressed is sucked and flows out and a high-pressure port from which high-pressure refrigerant before being decompressed is discharged and flows in; a driving and electric-power generating member that has a function of applying the driving power to the compression and expansion member and a function of generating electric power by the mechanical energy; a refrigerant pressure-feeding member that pressure-feeds refrigerant to the compression and expansion member, the refrigerant pressure-feeding member having a refrigerant suction side and a mechanical sliding portion; a first communicating part through which the refrigerant suction side of the refrigerant pressure-feeding member communicates with the mechanical sliding portion of the refrigerant pressure-feeding member; and a second communication part that makes the low-pressure port communicate with the mechanical sliding portion, wherein the second communication part separates lubricating oil from the vapor-phase refrigerant and supplying the lubricating oil to the mechanical sliding portion. 